Strap dispenser and method



Nov. 16, 1965 o. DERRICKSON Filed April 18, 1963 United States Patent 3,218,002 STRAP DISPENSER AND METHOD Michael 0. Derrickson, Norwood, Pa., assignor, by mesne assignments, to FMC Corporation, San Jose, Calif., a corporation of Delaware Filed Apr. 18, 1963, Ser. No. 273,944 6 Claims. (Cl. 242-129) This invention relates to a strap dispenser which, while useful for dispensing strap from a ribbon wound coil, is most advantageously useful for dispensing strap from a mill wound coil. The invention also relates to a novel method of unwinding strap from a mill wound coil without rotating the coil and without introducing a twist into the strap as it is unwound.

Strap for binding boxes, bales, bundles and the like is commonly packaged or supplied in coils known as mill wound and ribbon wound. A mill wound coil is an annulus having a thickness greater than the strap width, usually not more than about six times the strap width, wherein the strap convolutions crisscross so that the strap is evenly distributed throughout the coil. A ribbon wound coil is one wherein the thickness of the coil is equal to the width of the strap, that is to say each convolution of the strap exactly overlies the previous convolution. Both types of coils are supplied without cores, the windings being held in annulus form during shipment by Wires, straps or the like extending thereabout radially of the bundle. Due to the fact that a mill wound coil of any given diameter obviously contains more strap and is heavier than a ribbon wound coil of similar diameter, the various problems involved in providing a suitable dispenser for the strap are exaggerated or intensified when dealing with mill wound coils. Unwinding the strap from a mill wound coil is also more diflicult, particularly when the strap is withdrawn at high speed, due to the crisscrossing of the strap convolutions. As mentioned, the present invention may be used for dispensing strap from a ribbon wound coil but its greatest utility is in connection with mill wound coils.

With coreless coils the strap may be withdrawn from either the inside or the outside of the coil, provided the coil is mounted or positioned so that the inner end of the strap is available. While many dispensers provide for mounting the coil in such manner that the inner end of the strap is not available, it is not uncommon to mount the coil on a platform in such a manner that access may be had to the inner end of the strap. If the strap is Withdrawn radially of the coil from either the inner or outer end, provision must normally be made to allow the coil to rotate, for otherwise the strap will not unwind. With a rotatably mounted heavy mill wound coil, and particularly where it is desired to intermittently withdraw strap at a fairly rapid rate, there is a problem of overcoming the inertia of the coil both when starting and stopping the withdrawal. Providing a dispenser able to cope with these inertia problems is usually expensive. If the coil of strap is allowed or forced to remain stationary, the strap may be withdrawn perpendicular to the plane of the coil but this method will normally cause a twisting of the strap, that is the strap will twist through 360 for each convolution removed from the coil. Such twisting is highly objectionable when the strap is used for binding large objects and is completely unsatisfactory when the strap is being used with automatic equipment.

It is an object of this invention to provide a method of unwinding a strap from a stationary coil, particularly a mill wound coil, without introducing a twist into the strap.

Another object of the invention is to provide an improved strap dispenser characterized by an absence of 3,218,002 Patented Nov. 16, 1965 'ice moving parts which facilitates the withdrawal of strap from a large stationary coil without the introduction of a twist into the strap.

Other and further objects, features and advantages of the invention as well as the means for achieving the same will become apparent as the description of a preferred embodiment thereof proceeds.

As previously indicated, when an elongated member is withdrawn from a coil without rotating the coil the normal effect is that one turn of twist is inserted into the member for each convolution removed from the coil. Even when the member, e.g., a wire, has a circular crosssection, this twisting is usually objectionable and when the member is a strap or ribbon it is even more objectionable since it is normally desirable for the strap or ribbon to lie flat against the object with which it is to be associated. Briefly, the method by which the present invention avoids the twisting is that a length of strap is withdrawn from the center of the stationary coil and formed into a generally conoidal roll with the axis of the roll coinciding with the transverse axis of the coil and the large end of the cone form lying generally in the plane of the coil. The end of the strap is then pulled from the smaller outer end of the cone form, which is not a complete cone but rather a frustum of a cone. As the strap leaves the conoidal roll it is passed through a stationary guide so that a pull on the strap causes the roll to rotate whereby no twist is inserted into the strap. This .method will be explained more fully as the specification proceeds.

Referring now to the drawing:

FIG. 1 is a vertical center section through the dispenser; and

FIG. 2 is an isometric view showing the dispenser in use.

According to a preferred embodiment, the dispenser is formed of a plurality of wires individually indicated generally at 10. Each wire 10 has a vertically extending segment 12 at one end adjacent which is a horizontally extending segment 14. Segments 12 are arranged in a circle and a wire ring 16 is welded to the upper ends of said segments. A wire ring 18 is welded to the underside of horizontal segments 14 and said horizontal segments extend radially inward from the circularly arranged segments 12. At the inner end of segment 14, the wire is bent upward at an angle of approximately to the horizontal to provide a sloping segment 20 from the upper end of which the wire is bent at 22 out of alignment with segment 20 to provide a terminal segment 24.

The sloping segments 20 of the various wires 10 together or as a group form a truncated cone or frustum of a cone extending axially of the circular base provided by the horizontal segments 14, with the larger base of the frustum lying in the plane of the horizontal segments. The smaller base of the frustum formed by segments 20 is parallel to the larger base and lies in the plane of the bends 22. A pair of wire rings 26 and 28 are Welded to sloping segments 20 to retain said segments in this overall frusto-conical configuration. The terminal segments 24 of the wires 10 also form a frustum of a cone, said frustum being smaller than the one formed by segments 20. The smaller frustum is inverted and its smaller base is coincident with the smaller base of the larger frustum. At the outer ends of segments 24 a pair of wire rings 30 and 32 are welded to opposite sides thereof, said rings together with the wire segments 24 providing a plurality of selectably usable guide openings or strap accommodating passageways, as will presently appear.

In use, a coil, for example a mill wound coil 34, of strap is placed in the basket formed by the lower portions of wires 10 and a length of strap is unwound from the inner portion of the coil and arranged in the form of a generally conoidal roll by winding the same a few times about the conically arranged segments 20. The end of the strap is then inserted through one of the guiding passageways defined by rings 30 and 32 and the terminal portions 24 of wires 10. The width of the guiding passageways is such that the strap cannot twist as it passes therethrough and, of course, the selected passageway defines a definite point of departure for the strap leaving the dispenser. In FIG. 2, the conoidal roll of strap is indicated at 36 and it will be observed that the windings of the roll are laterally displaced and of ever decreasing diameter from bottom to top.

As the strap departs from the top of roll 36 it is guided tangentially and transversely of the roll about the inverted cone form to the selected fixed guide passageway. When the strap is pulled from the dispenser, windings are removed from the top of roll 36 and in order to permit this the roll must of course rotate since the point of departure of the strap from the roll is effectively fixed. The upper windings of roll 36 cannot move up any further than the wire bends 22 because these upper windings are too small of a diameter to pass about the outwardly directed wire segments 24. Thus, the small end of the cone frustum formed by the strap in roll 36 is restrained by the inverted cone frustum formed by the terminal portions 24 of the wires from moving away from the plane of mill roll 34. As roll 36 rotates due to removal of strap from the smaller end thereof more strap is withdrawn from mill wound coil 34 and begins to progress helically upwards about the frusto-conically arranged segments 20. There is no fixed guide for the strap in the vicinity of coil 34 so that it is not necessary for the coil to rotate in order for the strap to move from said coil onto the larger lower end of rotating roll 36. The actual point where the strap first begins to engage the wire segments 20 continually shifts around the base of the cone in the direction opposite to the longitudinal movement of the strap.

As the wrappings or convolutions forming roll 36 move upward they begin to overlap but never to the extent that one convolution directly and entirely overlies the preceding one. This overlapping provides a snubbing action requiring a positive pull on the strap to remove it from the dispenser but so long as there is room at the bottom of the conical roll to accommodate another convolution the strap may be pulled quite easily. When the cone frustum becomes filled, the lower windings bind so that it is no longer possible to rotate roll 36 and it is then necessary to cut the strap adjacent the bottom of the cone in order to pull any more strap from the dispenser. After the strap is cut and the part forming the conical roll has been used up, the end is again taken from the inside of the coil 34 and wound about the wire segments 20 as above described. It should be pointed out that because of the close overlapping of the convolutions, a considerable length of strap can be accommodated on the conically arranged wire segments 20 and since strap is being withdrawn from the top of the cone at the same time that it is being wound onto the bottom of the cone a much more considerable length of strap may be withdrawn before it is necessary to restart the operation than can actually be accommodated at one time in the conical formation.

The provision of a plurality of guides at the top of the dispenser enables the strap to be withdrawn in any direction merely by lacing the strap through the appropriate guide. Without this feature it would be necessary to orient the entire dispenser in order to direct the strap in the desired direction.

While it is obvious that the wire construction of the dispenser makes for low cost and light weight there is another advantage that should be pointed out, namely, that there is very little friction of the strap against the wires as the strap proceeds up and about the conically arranged segments 20 and thus not much pull is required to unwind the strap. However, the novel method of unwinding strap from a stationary coil without twisting the strap may be practiced with the aid of apparatus having a different construction. Also, the basic advantages of the hereinabove-described dispenser may be obtained by using other construction materials so long as the over-all outline of the dispenser is kept substantially as described.

Having thus described the invention, what is claimed is:

1. A strap dispenser comprising a substantially circular holder including a stationary platform for stationarily supporting a coil of strap, frusto-conical guide means fixed to said platform and extending axially therefrom, said guide means having a large base lying in the plane of said platform and a small base parallel to the large base, and stationary strap guiding means carried by said frustoconical guide means, said stationary strap guiding rneans comprising a strap-accommodating passageway defining a definite point of departure for the strap leaving the dispenser.

2. The strap dispenser set forth in claim 1 wherein said stationary strap guiding means comprises, in addition to said strap-accommodating passageway, an inverted frustoconical guide the small base of which is coincident with the small base of the first-mentioned frusto-conical guide means.

3. A strap dispenser formed of a plurality of Wires providing a substantially planar base for supporting a coil of strap, said wires being bent away from the planar base inwardly of the coil adapter to be supported on the base to provide a truncated cone configuration having a large base located in the plane of said planar base whereby strap withdrawn from the center of the coil may progress helically around the conical configuration with loops of ever diminishing diameter, and means connected to said wires providing a passageway for directing the strap away from the small base of the truncated cone.

4. A strap dispenser formed of a plurality of wires, said Wires providing a basket having a substantially circular horizontally extending bottom for accommodating a mill wound coil of strap, said wires extending upwardly and inwardly from the bottom of the basket to provide a frustoconical strap support about and up which the strap pulled from the center of the mill wound coil may progress helically, said wires extending upwardly and outwardly from the top of the frusto-conical strap support to provide an inverted truncated cone formation for leading the strap away from the top of the frusto-conical strap support, and guide means defining a definite point of departure for the strap leaving the dispenser.

5. The strap dispenser set forth in claim 4 comprising a pair of rings secured to opposite sides of the wires at the outer end of the truncated cone formation, said rings together with the wires located therebetween forming a plurality of guide means selectively employable to establish the point of departure for the strap leaving the dispenser.

6. A method of unwinding a strap from the center of a mill wound coil of strap without twisting the strap comprising stationarily supporting a mill wound coil, withdrawing the end of the strap from the center of the coil and arranging a length of the strap in the form of a frustum of a cone with the leading end of the strap extending from the small end of the frustum, and pulling the end of the strap through a fixed guide to thus cause the length of the strap which is arranged in the form of a frustum to rotate as the strap is pulled through the fixed guide.

References Cited by the Examiner UNITED STATES PATENTS 2,186,928 1/1940 Koch 242129 2,286,460 6/1942 Brown 242128 3,098,617 7/1963 Day 24255.11

MERVIN STEIN, Primary Examiner. 

1. A STRAP DISPENSER COMPRISING A SUBSTANTIALLY CIRCULAR HOLDER INCLUDING A STATIONARY PLATFORM FOR STATIONARILY SUPPORTING A COIL OF STRAP, FRUSTO-CONICAL GUIDE MEANS FIXED TO SAID PLATFORM AND EXTENDING AXIALLY THEREFROM, SAID GUIDE MEANS HAVING A LARGE BASE LYING IN THE PLANE OF SAID PLATFORM AND A SMALL BASE PARALLEL TO THE LARGE BASE, AND STATIONARY STRAP GUIDING MEANS CARRIED BY SAID FRUSTO-CONICAL GUIDE MEANS, SAID STATIONARY STRAP GUIDING MEANS COMPRISING A STRAP-ACCOMMODATING PASSAGEWAY DEFINING A DEFINITE POINT OF DEPARTURE FOR THE STRAP LEAVING THE DISPENSER. 